Variable-speed drive



' Aug. 3, v1926.

` M. T. wEs-roN VARIABLE SPEED DRIVE Filed sept. ze, '1925 3 Sheets-Shut 1 INVENTOR. VMI/tf 3. www

Aug. 3 1926. 1,594,396

M. r-wl-:sTN c VARIABLE SPEED DRIVE INVENTOR.

VMM 1Min/tn" riff l Y Aug. 3 i 1926. 1,594,396

M. 1'. WESTON VARIABLE SPEED DRIVE Filed sept. 2a. 1925 s shuts-shut :s

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IIIIIIIIIII u i, ,-6 INVENTOR.

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Aimitated Aug. 3, 1926.

UNITED STATES MILTON TWESTON, OF NEW YORK, N'. Y.

VARIABLE-SPEED DRIVE.

Application flied September 26, 1925. Serial No. $8,928.

This invention relates to variable speed drives such as that shown and described in my copending application on variable speed driving mechanism, which was filed in the United States Patent Office on April 17, 1925 and serially numbered 23,835.

The primar object of my invention is to provide varialile speed driving mechanism of improved construction by means of which the variations of speed in a machine or machine part may be regulated to an extreme degree of precision irrespective of the range oia variation in speed of the parts through which power is transmitted to said machine or part.

One of the 'objects of the tion is to provide an improve mitting unit comprising positively connected parts by means of which a machine or machine part may be set in motion, accelerated or retarded by extremely fine increments or deerements in speed from a motor or engine running at full speed, such, for example, as a synchronous motor.

Another object of my invention is to provide an improved dual variable speed motor control for variable speed mechanisms.

Another object of invention is to provide an improved variable speed drive for the several sections of a paper-makin machine present invenand whereby the relative speed o said sections may be regulated with an extreme degree of precision.

Other and further objects of invention will a pear in the specification and be pointe out in the claims in connection with the accompanylng drawings which show a preferred embodiment of my invention and in which,

Figure l is a top plan view of a papermaking machine having my improved'variable speed drive applied thereto.

Figure 2 is a wiring diagram for the dual motor control.

. Figure 3 shows a wiring diagram for one of the main motor circuits.

Figure 4 is an axial section of one of the main power-transmission units, said section being taken on the line 1 -4, Figure 6, parts being broken away and parts shown in side elevation.

Figure is a top plan view of the'same with the cover removed, corresponding to.

the line 5--5 of Figure 6.

Figure 6 is a vertical section corresponding to the line 6-'-6, Figure 8.

power-trans-Vy Figure 7 is a section on the line 7-7, Fi re4 6; and

igure 8 is a top plan view of one of the power-transmission units as applied to a vpaper-machine section driven from a power shaft which is common to a plurality of said paper-machine sections.

In its' present embodiment, my invention is adapted to a pa er-makin machine such as that shown an describe in my aboveidentified copending., application. According to the present case, a finer degree of regulation may be had in the variable speedf controlling mechanism than is possible in my earlier case and such regulation is applicable to all speeds. Furthermore, according to this application, I employ only positively geared means and eliminate entirely the clutch or the ratchet means employed in my above-identified application. The present invention contemplates the use of a diferential gear control, which may be similar in construction to the main variable speed clement, and in which two or more independently operable positively geared elements either separately or jointly aect a third holding or controlling element so as to obtain any desired speed regulation over the maximum speed range.

According to my application Serial-Number 23,835, I use a single variable speed motor 'v which is adapted to produce a maximum variation (of say 100%) in a particular unit through one set of .change speed gears and a relatively low variation (of say 5%) through an alternate set of change speed gears. Under these conditions, when the motor v is operating through the change speed gears giving the maximum variation, each step in the controller will produce a relatively large degree of variation and the increment of change in the speed of the paper machine section will be correspondingly large. On the other hand, when the motor fv is operating through the change speed gears giving the minimum variation, each step in the controller will produce a relatively small degree of variation and the increment of change in the speed of the paper machine section will be correspondingly l small. Thus, a very fine degree of regulation may be obtained but such variation takes place only at the maximum speed of` ,the cage.

eral units when said units are driven from a common power shaft S.

Power-transmission unit.

Referring more particularly to Figures 4, 5, 6, 7, and 8, in the present embodiment of my invention, each power-transmitting un1t includes a base 1 on which is mounted a casing comprising a bottom section 2 and a removable cover section 3. In this casing 1s mounted a revolvable cage C comprising a cylindrical shell 4 and two end discs 5 and 5b secured in opposite ends of the said cylindrical shell. Each of the end discs 5:? and 5* has a hollow trunnion 6a and 6b projecting axially and mounted to revolve in suitable bearings 7 a and 7 b formed partlyin section 2 and partly in section 3 of said casing. A driving shaft 8 is mounted to revolve in the hollow bore of the trunnion 6a and carries a driving pinion 9 keyed to it within the cage C. As shown in Figures 4 and '5, the driving shaft 8 is directly connected to a main driving motor M which is preferably of the synchronous or constant speedtype and mounted on the base 1. According to Figures 1 and 8, said driving shaft 8 is driven from a power shaft S which may be common to a plurality of sections of a paper-making machine. For this purpose, a bevel pinion 10 which is keyed to shaft S, meshes with a bevel gear 11 keyed to driving shaft 8 with, in an extension 12 of the casing 2. Within the revolving cage 4, a spur pinion 9 keyed to shaft 8 is coaxially arranged with respect to a driven gear 13 and connected thereto by planetary gears 14 and l5. Said driven gear 13 is provided with an extended sleeve hub 13* which is journalled freely upon the reduced portion 8 of said driving shaft within hollow trunnions 6a of the end disc 5. `Parallel to the axis of the cage C and at equal distances therefrom the planetary gears 14 and 15 are arranged in three clusters to rotate in suitable bearin s inthe end discs 5a and 5" in each of t e revolving cages C. In operation, the driving pinion 9, cluster gears 14 and 15, and driven gear 13, function as a simple speed reducer when the cage C is held so as not to revolve, i. e. the extendedsleeve hub 13a will have a fixed reduced speed with respect to the driving shaft 8. Revolving the cage in either direction, however, introduces a variation in the speed of the sleeve hub 13 with respect to its normal reduced speed when the cage is fixed. When the cage C is revolved in the same dlrection as the driving shaft 8, the speed of the sleeve hub 13u is increased at a rate which is proportional to the speed of Whenthe cage C is revolved in the direction opposite to the direction of rotation of the driving shaft 8, the speed of the sleeve hub 13 will be reduced in proportion to the speed of the cage. When a certain speed of counter rotation of the cage C is reached, the (sleeve hub 13'* will remain stationary and any further increase in the speed of counter rotation will cause the sleeve hub 13a to rotate backwardly or oppositely to its normal direction of rotation.

For controlling the revolutions of each of the cages C, a worm wheel 16 may be keyed to the trunnion 6b to mesh with a worm 17 on a transverse shaft 18.

Variable speed mechanism control.

Referring more especially to Figure 6, it will be seen that the shaft 18 which carries the main holding or controlling worm 17, is journalled at one end in a bearing 19 carried by the casing 2, the other end of said `shaft being journalled in a bearing 62 in wardly from bearing 62 around the worm shaft 18. A driving shaft 66 which is journalled within the trunnion 71 is arranged in axial alignment with the worm shaft 18 but rotatable relatively thereto, a spur being formed integrally therewith. The outer end of shaft 66 may be coupled directly to a small variable speed motor/v1 and may be driven thereby or under certain conditions to be hereinafter referred to, maybe held stationary by an electromagnetic brake 68 which is arranged to operate upon the projecting end of the armature shaft of said motor ful. The coil 68aL of said magnetic brake is preferably arranged in series with the motor 'v1 as shown in Figure 2 an'd according to which the armature shaft may be released whenever the energizing current is turned on and immediately locked against movement as soon as the current is turned off. Arranged within the planetary support or cage C1, are clusters of planetary gears 69 and 70 which form a variable speed connection between driving gear 67 and driven gear 63. 4 y

Secured to the outer end of trunnion 71 which turns in the bearing on cap 64, is a worm wheel 16A which meshes with a worm 17A on the worm shaft 18A, the latte;` shaft extending transversely through the housing 60. The outer end of the Worm shaft 18A is -directly connected to a small variable speed motor v2 as shown in Figures 4, 7, and 8. It will be understood that while I. show the epicyclic form ofl differential gearing on account of its reliable and-simple. construction, any form of differential gearing may be used for the purpose.

In Figure 1 of the drawings is shown a preferred adaptation of my invention t0 a paper-making machine,` said machine comprising a couch section A, 1st. press B, 2d. press D, 1st. dryer E, 2d. dryer F, and calender sections G, G. Said sections with the exception of calenders G, G, are directly and positively connected to the power shaft S through the variable speed units A1, B1, D1, E1, and F1 which have been hereinbefore described. As shown in Figures 1 and 4, said common vpower shaft is preferably connected to motor M through a variable speed unit,

H1 of similar construction, a clutch 56 being interposed between shaft S and variable speed unit H1.. By means of this construction and under the control of variable speed motors /v1 and 'v1 connected to the unit H1, power shaft S may be accelerated from rest to full speed by motor M while the latter is operating at full speed, thus making it possible to secure the advantages of a fixed 'speed or synchronous motor for the main driving motor M. The variable speed units A1, B1, etc. may be similarly utilized for separately accelerating the corresponding sections of the paper machine from the power shaft S irrespective of the speed of the latter or said sections may be accelerated together with ower shaft S through unit H1. In a simi ar manner, calender sections G, may be accelerated or retarded throu h variable speed units G1, G1, and when esired and Wherever the conditions of the web are suitable the acceleration or retardation of any particular section of the p a er machine, may be automatically control ed:

by the web at those .points in the manner shown and described in my above-identified copending application. Simple electrical diagrams for controlling the variable speed motors v1 and o2 and for starting and stop- Rilng the fixed speed or synchronous motor are shown in Figures 2 and 3 of the drawings.

Referring to Figures 4, 5, and 6, we will assume that all parts are at rest. When it is desired to start"any given unit vsuch asA one of the calender units G', G the jaw clutch 56 (which also functions as a flexible coupling) is disengaged and motor M (pref erably synchronous) is brought up to full speed b means of a suitable starter represented iag'rammatically in Figure 3. The small auxilia motor V1 is also brought up to substantial y full speed, the ratio of the differential gearing in the cage C being such that at approximately full spee'd the motor V1 will permit the cage C to revolve to cause the sleeve hub 131, on which one member of the jaw clutch 56 is mounted, to come te "est. The jaw .motor having but a tor M which continues to run at full or synchronous s eed. Inasmuch as the worm 17 is designe as a holding worm for restrainl `ing the revolution of cage C,y no load is thrown on the small motor V1 which has only to overcome the frictional work in the gearing. p Y

As previously explained, one step in th controller for motor V1 will cause an increment ofvchange in the speed of the-paper machine section which, though relatively small, is yet too eat to give the necessary 'degree of regulation for pro erly adjusting the draw in the paper web. In order to secure the necessary refinement in this adjustment, I use a second auxiliary motor V2 .which operates upon the same differential gearing as motor V1 but at a relatively greater speed reduction through worm 12'1 and worm wheel 16". For this reason one step in the controller for 'small motor V2 will cause a very small change in the paper speed for that section at small increment of chan e in s eed is superimposed upon the spe pro uced by the auxiliary motor V1 and is therefore operatable at any and all speeds of motor V1 from zero to full speed, while the main motor M continues to run at its constant or synchronous s eed.

A similar starting of the paper machine sections A, B, D, E, and F, may be effected from power shaft S thru the operation of the clutch-couplings 56 an'd the control of variable speed units A1, B1, D1, and F1 after said power shaft has been accelerated thru variable speed unit H1 and the motor M connected thereto. y v

It will be understood from Figures 2 and 6, that whenever variable speed motor lv1 is deenergized, magnetic brake coil 681 will be deenergized and the brake 68 automatically applied. 2, and 6, it will be seen that this condition may hold without interfering with the variable speed control of notor 'l1-1.

It will be understood from the foregoing description that by employing the positively geared variable speed mechanisms for accelerating the several sections of a papermaking` machine from a condition of rest, it becomes possible to employ a synchronous fraction of the -power of motors commonly employed for driving machines of this character. By means of that point. This v From an inspection of Figures 1, g

synchronous motor, it yet becomes possible,-

by an adaptation of my invention toward this end, to secure all the advantages of such a motor by accelerating it up to full speed before any load of consequence is thrown upon it and afterwards applying the load thereto in such a gradual manner as not to lessen the speed of said motor. This improved result is made possible by the superimposed regulation of one of the small variable'speed motors upon the stepby-step regulation of the other of said variable speed motors.

1. Power transmission mechanism comprising driving and driven elements, planetary gearing operatably connecting said elements, means including planetary gearing for operating the first-mentioned planetary ,gearing to vary the power-transmission between said driving and driven elements, and means for operatin the second-mentioned planetary gearing or varying the powertransmission to the first-mentioned planetary gearing.

2. Power transmission mechanism comprising a power shaft, a driven shaft, planetary gearing operatably connecting sald shafts, a motor, and planetary gearing connecting said motor to the first-mentioned planetary gearing for varying the power transmission between said motor and the first-mentioned planetary gearing.

3. Power transmission mechanism conrprising a driving ear, a driven gear, planetary gears operata ly connecting -said gears, means including planetary gears for revolving the first-mentioned planetary gears for varying the power transmission between said driving and driven gears, and means for revolving the second-mentioned planetary gears for varying the rate of change in the power-transmission between said gears.

4. The combination with variable speed power-transmitting planetary gearing, of a power-source connected to and supplyinv power to said planetary gearing, a second power-source for imparting the planetary movements to said planetary gearing, other variable speed planetary gearing interposed between said second power-source andthe first-mentioned planetary gearing, and means for contro ling the planetary movements of the second-mentioned planetary gearing.

5. Power transmission mechanism comprising a power-shaft, a driven shaft, positive variable speed mechanism connecting 'l0 prising a power shaft, afdriven shaft, variable speed mechanism connecting said shafts, a variable speed motor, variable speed mechanism connecting said motor to the firstmentioned variable speed mechanism, and a variable speed motor connected to the second-mentioned variable speed mechanism.

7 Power transmission mechanism comprising a power shaft, a driven shaft, variable speed mechanism connecting said shafts, a reversible motor, variable speed mechanism connect-in said motor to the first-mentioned variale speed mechanism for varying the power transmission between said power and driven shafts, aiid a4 variable .speed motor connected to the secondmentioned variable speed mechanism.

'8. Power transmission mechanism comprising a power shaft, a driven shaft, variable speed mechanism connecting said shafts a reversible motor, other variable speed mechanism connecting said motor to the first-mentioned variable speed mechanism for varying the power transmission between said power and driven shafts, and a motor connected to the second-mentioned variable speed mechanism.

9. In a machine of the character described, the combination with a main driving motor, of a machine section to be driven thereby, power connections between said motor and machine section including variable speed mechanism, and power-driven connections including other variable speed mechanism for controlling the operation of the firstlnentioned variable speed mechanism.

10. In a machine of the character described, the combination with a main driving motor, of a machine section to be driven thereby, power connections between said motor and machine section including positive variable speed mechanism, an auxiliary motor, power connections between said auxiliary motor and said variable speed mechanism including other positive variable speed mechanism, a second auxiliary motor, and means for separately controlling said auxiliary motors.

11. In a machine of the character described, the combination with a synchronous motor, of a machine section to be driven thereby, (power connections between saidA motor an machine section including variable speed mechanism, and power-driv'n connectionsaincluding variable speed mechanism for controlling the operation of the first-mentioned variable s eed mechanism.

12. In a machine of t e character described, the combination with a main driving motor of a machine section to be driven thereby, power connections between said motor and machine section including variable speed mechanism, an auxiliary motor, power connections between said auxiliary nmior and said vnriable speed mechanism including other variable speed mechanism,

a second auxiliary motor, means for separately controlling said auxiliary motors, and means under the control of one of said motor controlling means for braking the armature shaft of that motor. 13. In a machine of the character described, a main driving motor, a main drive shaft, variable speed mechanism connecting` said motor to said shaft, power driven variable speed mechanism connected to the Iirstmentioned variable speed mechanism, other power driven variable speed mechanism connected to the second-mentioned variable speed mechanism, a machine section to be driven, and power connections including variable speed mechanism arranged between said main drive shaft and said vmachine section. 14. In a machine of the character described, a main driving synchronous motor, a main drive shaft, variable speed mechanism connecting said motor to said shaft,

rariable speed mechanism for controlling the first-mentioned variable speed mechanism, a machine to be driven, and power connections arranged between said main drive shaft and said machine section.`

15. In a machine of the character described. a main driving motor, a main drive shaft, variable speed mechanism connecting said motor to said shat, power driven variable speed mechanism connected 4to the first-mentioned variable s eed mechanism, other power driven varia le speed mechanism connected to the second-mentioned variable speed mechanism,l a machine section to be driven,'power connections inclu-.iing variable speed mechanism arranged between said main drive shaft and said machine section, power-driven variable speed mechanism connected to the last-mentioned variable speed mechanism, and other powerdriven variable speed mechanism connected to the last said power-driven variable speed mechanism.

16. In a machine of the character described, a main driving synchronous motor,

a mam drive shaft, variable speed mechanism connecting said motor to said shaft, aV

variable speed motor for controlling said other variable speed mechanism inter osed between said variable speed motor an the first-mentioned variable speed mechanism, a

machine section to be driven, and power connections betweenfsaid main drive shaft and said machine section.

17. The combination with variable speed power-transmitting planetary gearing, of a synchronous motor connected to said planetary gearing, a variable speed motor for imparting the planetary movements to said planetary gearing, other planetary gearing interposed between said variable speed motor and the first-mentioned planetary gearing, andy means for controlling the planetary movements of the second-mentioned planetary gearing. A

18. In a machine of the character described, the combination with a synchronous motor and a shaft to be driven thereby, voi? variable speed driving connections between said motor and shaft, a variable speed motor for operating said connections, and other variable speed connections interposed between the variable speed motor and the firstmentioned variable speed connections.

19. In a .mach-ine of the character described, a machine to be driven, a synchro nous motor for driving said machine, driving connections between said synchronous motor and said machine, said connections including variable speed mechanism, a variable speed reversible motor connected therel to, other variable speed mechanism for modifying the operation of the lirst-ment-ioned variable speed mechanism, and a variable speed motor connected to said other variable speed mechanism.

20. In a machine of the character described, the combination with a synchronous motor and a shaft to be driven\ thereby, of driving connections between said motor and shaft, including variable speed mechanism, a motor for controlling the operation of said variable speed mechanism, and other variable speed mechanism interposed between said motor ar dl the first-mentioned variable speed mechanism.

21. In a machine of the character described, a machine to be driven, a synchronous motor for driving said machine, driving connections between said synchronous motor and said machine, said connections 1ncluding variable speed mechanism, and power-driven connections including. other variable speed mechanism for controlllng the operation of the first-mentioned variable speed mechanism.

22. In a machine of the character described, the combination with a synchronous motor and a shaft to be driven thereby, of driving connections between said motor and shaft, including yvariable speed mechanism, a variable speed motor for controlhng the operation of saidvariable speed mechamsm other variable s d mechanism interposed between the variable speed motor andthe first-mentioned variable speed mechanlsm,

-through which itis driven, a synchronous motor provided with a rotaryv shaft, gears carried by said shafts, planetary gears transmitting power between said shafts, a variable speed motor, connections between said Imotor and planetary gears for revolving the latter, `said connections including planetary variable speed gearing, a planetary movement for revolving the last-mentioned planetary gears, and a variable speed motor connected to said planetary movement.

24. In a paper-making machine, a plurality of paper machine sections, power-driven positively-geared variable speed mechanism for driving each ofsaid sections, variable positively-operated means for accelerating or retarding each variable speed mechanism, and other variable positively-operated means for controlling the amount of such acceleration or retardation.

25. In a paper-making machine, a plurality of paper machine sections, power-driven positively-geared variable speed mechanism for driving each of said sections, variable positively-operated means for accelerating or retarding each variable speed mechanism Within changing speed limits, and other variable positively-operated. means for controlling the amount of such acceleration or retardation.

26. In a paper-making machine, a plurality of paper machine sections, power-driven positively-geared variable speed mechanism for driving each of said sections, variable positively-operated means for accelerating or retarding each variable speed mechanism, and other variable positively-operated means for controlling the amount of such acceleration or retardation. 27. In a paper-making machine, a plurality of paper machine sections, power-driven positively-geared variable speed mechanism for.- driving each of said sections, variable positively-operated means for accelerating or `retarding each variable speed mechanism relatively to another of said variable speed mechanisms and within changing speed limits, and other variable positively-'operated means for controlling the amount of such acceleration or retardation.

28.. A power-transmission unit comprising a main driving motor, variable speed mecha- Lacasse a main driving motor, variable speed mechanism driven thereby, means for varying the operation of said variable speed mechanism including a second variable speed mechanism, and means for varying the operation of the second-mentioned variable speed mechanism.

30. .A power-transmission unit comprising a synchronous motor, variable vspeed mechanism driven thereby, means for varying the operation of said variable speed mechanism including av variable speed motor and a second variable speed mechanism, and means for controlling the operation of the secondmentioned variable speed mechanism.

3l. A power-transmission unit comprising a main driving motor, variable speed mechanism driven thereby, a variable speed motor and a second variable sied mechanism connected to and varying t e Operation of said variable speed mechanism, and a variable speed motor connected to and varying the operation of the second-mentioned variable speed mechanism. I

32. The combination'with a yplurality of paper-machine sections, of a ower shaft common thereto, variable spee mechanism including planetary gearing for connecting each of saidy machine sections to said powei` shaft, variable speed means for revolving said planetary gears, said variable Spee means including a motor and variable speed connections with planetary gears, and a variable speed motor for revolving the lastmentioned planetary gears.

33. The combination with variable speed power-transmitting planetary gearing, of a constant speed power-source connected to and supplying power to said planetary gearing, a variable speed power-source for imparting the planetary movements to said planetary gearing, other variable speed planetary gearing interposed between said variable speed power-source and the firstmentioned planetary gearing, and means for controlling the planetary movements ofthe second-mentioned planetary gearing.

MILTON T. wias'roN,

lic 

